org.w3c.dom.ls
Interface LSSerializer

public interface LSSerializer

A LSSerializer provides an API for serializing (writing) a
DOM document out into XML. The XML data is written to a string or an
output stream. Any changes or fixups made during the serialization affect
only the serialized data. The Document object and its
children are never altered by the serialization operation.

During serialization of XML data, namespace fixup is done as defined in [DOM Level 3 Core]
, Appendix B. [DOM Level 2 Core]
allows empty strings as a real namespace URI. If the
namespaceURI of a Node is empty string, the
serialization will treat them as null, ignoring the prefix
if any.

LSSerializer accepts any node type for serialization. For
nodes of type Document or Entity, well-formed
XML will be created when possible (well-formedness is guaranteed if the
document or entity comes from a parse operation and is unchanged since it
was created). The serialized output for these node types is either as a
XML document or an External XML Entity, respectively, and is acceptable
input for an XML parser. For all other types of nodes the serialized form
is implementation dependent.

Within a Document, DocumentFragment, or
Entity being serialized, Nodes are processed as
follows

Document nodes are written, including the XML
declaration (unless the parameter "xml-declaration" is set to
false) and a DTD subset, if one exists in the DOM. Writing a
Document node serializes the entire document.

Entity nodes, when written directly by
LSSerializer.write, outputs the entity expansion but no
namespace fixup is done. The resulting output will be valid as an
external entity.

If the parameter "
entities" is set to true, EntityReference nodes are
serialized as an entity reference of the form "
&entityName;" in the output. Child nodes (the expansion)
of the entity reference are ignored. If the parameter "
entities" is set to false, only the children of the entity reference
are serialized. EntityReference nodes with no children (no
corresponding Entity node or the corresponding
Entity nodes have no children) are always serialized.

CDATAsections containing content characters that cannot be
represented in the specified output encoding are handled according to the
"
split-cdata-sections" parameter. If the parameter is set to true,
CDATAsections are split, and the unrepresentable characters
are serialized as numeric character references in ordinary content. The
exact position and number of splits is not specified. If the parameter
is set to false, unrepresentable characters in a
CDATAsection are reported as
"wf-invalid-character" errors if the parameter "
well-formed" is set to true. The error is not recoverable - there is no
mechanism for supplying alternative characters and continuing with the
serialization.

DocumentFragment nodes are serialized by
serializing the children of the document fragment in the order they
appear in the document fragment.

All other node types (Element, Text,
etc.) are serialized to their corresponding XML source form.

Note: The serialization of a Node does not always
generate a well-formed XML document, i.e. a LSParser might
throw fatal errors when parsing the resulting serialization.

Within the character data of a document (outside of markup), any
characters that cannot be represented directly are replaced with
character references. Occurrences of '<' and '&' are replaced by
the predefined entities &lt; and &amp;. The other predefined
entities (&gt;, &apos;, and &quot;) might not be used, except
where needed (e.g. using &gt; in cases such as ']]>'). Any
characters that cannot be represented directly in the output character
encoding are serialized as numeric character references (and since
character encoding standards commonly use hexadecimal representations of
characters, using the hexadecimal representation when serializing
character references is encouraged).

To allow attribute values to contain both single and double quotes, the
apostrophe or single-quote character (') may be represented as
"&apos;", and the double-quote character (") as "&quot;". New
line characters and other characters that cannot be represented directly
in attribute values in the output character encoding are serialized as a
numeric character reference.

Within markup, but outside of attributes, any occurrence of a character
that cannot be represented in the output character encoding is reported
as a DOMError fatal error. An example would be serializing
the element <LaCañada/> with encoding="us-ascii".
This will result with a generation of a DOMError
"wf-invalid-character-in-node-name" (as proposed in "
well-formed").

When requested by setting the parameter "
normalize-characters" on LSSerializer to true, character normalization is
performed according to the definition of fully
normalized characters included in appendix E of [XML 1.1] on all
data to be serialized, both markup and character data. The character
normalization process affects only the data as it is being written; it
does not alter the DOM's view of the document after serialization has
completed.

Implementations are required to support the encodings "UTF-8",
"UTF-16", "UTF-16BE", and "UTF-16LE" to guarantee that data is
serializable in all encodings that are required to be supported by all
XML parsers. When the encoding is UTF-8, whether or not a byte order mark
is serialized, or if the output is big-endian or little-endian, is
implementation dependent. When the encoding is UTF-16, whether or not the
output is big-endian or little-endian is implementation dependent, but a
Byte Order Mark must be generated for non-character outputs, such as
LSOutput.byteStream or LSOutput.systemId. If
the Byte Order Mark is not generated, a "byte-order-mark-needed" warning
is reported. When the encoding is UTF-16LE or UTF-16BE, the output is
big-endian (UTF-16BE) or little-endian (UTF-16LE) and the Byte Order Mark
is not be generated. In all cases, the encoding declaration, if
generated, will correspond to the encoding used during the serialization
(e.g. encoding="UTF-16" will appear if UTF-16 was
requested).

Namespaces are fixed up during serialization, the serialization process
will verify that namespace declarations, namespace prefixes and the
namespace URI associated with elements and attributes are consistent. If
inconsistencies are found, the serialized form of the document will be
altered to remove them. The method used for doing the namespace fixup
while serializing a document is the algorithm defined in Appendix B.1,
"Namespace normalization", of [DOM Level 3 Core]
.

While serializing a document, the parameter "discard-default-content"
controls whether or not non-specified data is serialized.

While serializing, errors and warnings are reported to the application
through the error handler (LSSerializer.domConfig's "
error-handler" parameter). This specification does in no way try to define all possible
errors and warnings that can occur while serializing a DOM node, but some
common error and warning cases are defined. The types (
DOMError.type) of errors and warnings defined by this
specification are:

"no-output-specified" [fatal]

Raised when
writing to a LSOutput if no output is specified in the
LSOutput.

"unbound-prefix-in-entity-reference" [fatal]

Raised if the
configuration parameter "
namespaces" is set to true and an entity whose replacement text
contains unbound namespace prefixes is referenced in a location where
there are no bindings for the namespace prefixes.

"unsupported-encoding" [fatal]

Raised if an unsupported
encoding is encountered.

In addition to raising the defined errors and warnings, implementations
are expected to raise implementation specific errors and warnings for any
other error and warning cases such as IO errors (file not found,
permission denied,...) and so on.

getFilter()
When the application provides a filter, the serializer will call out
to the filter before serializing each Node.

java.lang.String

getNewLine()
The end-of-line sequence of characters to be used in the XML being
written out.

void

setFilter(LSSerializerFilter filter)
When the application provides a filter, the serializer will call out
to the filter before serializing each Node.

void

setNewLine(java.lang.String newLine)
The end-of-line sequence of characters to be used in the XML being
written out.

boolean

write(Node nodeArg,
LSOutput destination)
Serialize the specified node as described above in the general
description of the LSSerializer interface.

java.lang.String

writeToString(Node nodeArg)
Serialize the specified node as described above in the general
description of the LSSerializer interface.

boolean

writeToURI(Node nodeArg,
java.lang.String uri)
A convenience method that acts as if LSSerializer.write
was called with a LSOutput with no encoding specified
and LSOutput.systemId set to the uri
argument.

Method Detail

getDomConfig

The DOMConfiguration object used by the
LSSerializer when serializing a DOM node.
In addition to the parameters recognized by the
DOMConfiguration interface defined in [DOM Level 3 Core]
, the DOMConfiguration objects for
LSSerializer adds, or modifies, the following
parameters:

"canonical-form"

true

[optional] Writes the document according to the rules specified in [Canonical XML].
In addition to the behavior described in "
canonical-form" [DOM Level 3 Core]
, setting this parameter to true will set the parameters
"format-pretty-print", "discard-default-content", and "xml-declaration
", to false. Setting one of those parameters to
true will set this parameter to false.
Serializing an XML 1.1 document when "canonical-form" is
true will generate a fatal error.

false

[required] (default) Do not canonicalize the output.

"discard-default-content"

true

[required] (default) Use the Attr.specified attribute to decide what attributes
should be discarded. Note that some implementations might use
whatever information available to the implementation (i.e. XML
schema, DTD, the Attr.specified attribute, and so on) to
determine what attributes and content to discard if this parameter is
set to true.

false

[required]Keep all attributes and all content.

"format-pretty-print"

true

[optional] Formatting the output by adding whitespace to produce a pretty-printed,
indented, human-readable form. The exact form of the transformations
is not specified by this specification. Pretty-printing changes the
content of the document and may affect the validity of the document,
validating implementations should preserve validity.

false

[required] (default) Don't pretty-print the result.

"ignore-unknown-character-denormalizations"

true

[required] (default) If, while verifying full normalization when [XML 1.1] is
supported, a character is encountered for which the normalization
properties cannot be determined, then raise a
"unknown-character-denormalization" warning (instead of
raising an error, if this parameter is not set) and ignore any
possible denormalizations caused by these characters.

false

[optional] Report a fatal error if a character is encountered for which the
processor cannot determine the normalization properties.

"normalize-characters"

This parameter is equivalent to
the one defined by DOMConfiguration in [DOM Level 3 Core]
. Unlike in the Core, the default value for this parameter is
true. While DOM implementations are not required to
support fully
normalizing the characters in the document according to appendix E of [XML 1.1], this
parameter must be activated by default if supported.

"xml-declaration"

true

[required] (default) If a Document, Element, or Entity
node is serialized, the XML declaration, or text declaration, should
be included. The version (Document.xmlVersion if the
document is a Level 3 document and the version is non-null, otherwise
use the value "1.0"), and the output encoding (see
LSSerializer.write for details on how to find the output
encoding) are specified in the serialized XML declaration.

false

[required] Do not serialize the XML and text declarations. Report a
"xml-declaration-needed" warning if this will cause
problems (i.e. the serialized data is of an XML version other than [XML 1.0], or an
encoding would be needed to be able to re-parse the serialized data).

getNewLine

java.lang.String getNewLine()

The end-of-line sequence of characters to be used in the XML being
written out. Any string is supported, but XML treats only a certain
set of characters sequence as end-of-line (See section 2.11,
"End-of-Line Handling" in [XML 1.0], if the
serialized content is XML 1.0 or section 2.11, "End-of-Line Handling"
in [XML 1.1], if the
serialized content is XML 1.1). Using other character sequences than
the recommended ones can result in a document that is either not
serializable or not well-formed).
On retrieval, the default value of this attribute is the
implementation specific default end-of-line sequence. DOM
implementations should choose the default to match the usual
convention for text files in the environment being used.
Implementations must choose a default sequence that matches one of
those allowed by XML 1.0 or XML 1.1, depending on the serialized
content. Setting this attribute to null will reset its
value to the default value.

setNewLine

void setNewLine(java.lang.String newLine)

The end-of-line sequence of characters to be used in the XML being
written out. Any string is supported, but XML treats only a certain
set of characters sequence as end-of-line (See section 2.11,
"End-of-Line Handling" in [XML 1.0], if the
serialized content is XML 1.0 or section 2.11, "End-of-Line Handling"
in [XML 1.1], if the
serialized content is XML 1.1). Using other character sequences than
the recommended ones can result in a document that is either not
serializable or not well-formed).
On retrieval, the default value of this attribute is the
implementation specific default end-of-line sequence. DOM
implementations should choose the default to match the usual
convention for text files in the environment being used.
Implementations must choose a default sequence that matches one of
those allowed by XML 1.0 or XML 1.1, depending on the serialized
content. Setting this attribute to null will reset its
value to the default value.

getFilter

When the application provides a filter, the serializer will call out
to the filter before serializing each Node. The filter implementation
can choose to remove the node from the stream or to terminate the
serialization early.
The filter is invoked after the operations requested by the
DOMConfiguration parameters have been applied. For
example, CDATA sections won't be passed to the filter if "
cdata-sections" is set to false.

setFilter

When the application provides a filter, the serializer will call out
to the filter before serializing each Node. The filter implementation
can choose to remove the node from the stream or to terminate the
serialization early.
The filter is invoked after the operations requested by the
DOMConfiguration parameters have been applied. For
example, CDATA sections won't be passed to the filter if "
cdata-sections" is set to false.

write

Serialize the specified node as described above in the general
description of the LSSerializer interface. The output is
written to the supplied LSOutput.
When writing to a LSOutput, the encoding is found by
looking at the encoding information that is reachable through the
LSOutput and the item to be written (or its owner
document) in this order:

LSOutput.encoding,

Document.inputEncoding,

Document.xmlEncoding.

If no encoding is reachable through the above properties, a
default encoding of "UTF-8" will be used. If the specified encoding
is not supported an "unsupported-encoding" fatal error is raised.
If no output is specified in the LSOutput, a
"no-output-specified" fatal error is raised.
The implementation is responsible of associating the appropriate
media type with the serialized data.
When writing to a HTTP URI, a HTTP PUT is performed. When writing
to other types of URIs, the mechanism for writing the data to the URI
is implementation dependent.

Parameters:

nodeArg - The node to serialize.

destination - The destination for the serialized DOM.

Returns:

Returns true if node was
successfully serialized. Return false in case the
normal processing stopped but the implementation kept serializing
the document; the result of the serialization being implementation
dependent then.

Throws:

LSException - SERIALIZE_ERR: Raised if the LSSerializer was unable to
serialize the node. DOM applications should attach a
DOMErrorHandler using the parameter "
error-handler" if they wish to get details on the error.

writeToURI

A convenience method that acts as if LSSerializer.write
was called with a LSOutput with no encoding specified
and LSOutput.systemId set to the uri
argument.

Parameters:

nodeArg - The node to serialize.

uri - The URI to write to.

Returns:

Returns true if node was
successfully serialized. Return false in case the
normal processing stopped but the implementation kept serializing
the document; the result of the serialization being implementation
dependent then.

Throws:

LSException - SERIALIZE_ERR: Raised if the LSSerializer was unable to
serialize the node. DOM applications should attach a
DOMErrorHandler using the parameter "
error-handler" if they wish to get details on the error.

writeToString

Serialize the specified node as described above in the general
description of the LSSerializer interface. The output is
written to a DOMString that is returned to the caller.
The encoding used is the encoding of the DOMString type,
i.e. UTF-16. Note that no Byte Order Mark is generated in a
DOMString object.

Parameters:

nodeArg - The node to serialize.

Returns:

Returns the serialized data.

Throws:

DOMException - DOMSTRING_SIZE_ERR: Raised if the resulting string is too long to
fit in a DOMString.

LSException - SERIALIZE_ERR: Raised if the LSSerializer was unable to
serialize the node. DOM applications should attach a
DOMErrorHandler using the parameter "
error-handler" if they wish to get details on the error.